Holocene climate variability and its feedbacks to hydrology and vegetation dynamics in South Africa: Insights from compound-specific stable carbon (d13C) and hydrogen (dD) isotopes

Abstract

This thesis aims to advance the understanding of Holocene climate changes and their environmental consequences in South Africa using plant wax derived n-alkanes and their compound-specific stable carbon and hydrogen isotopes (d13Cwax, dDwax). The first part deals with a source-to-sink approach of terrestrial organic material (TOM) deposited in the mudbelt offshore western South Africa. It is shown that TOM in the northern mudbelt is mainly delivered by the Orange River and contains an integrated homogenous catchment signal. The second part deals with the applicability of dDwax as a hydrological recorder using soil samples from across South Africa. It is shown that dDwax suits well as qualitative hydrological proxy in the summer rainfall zone (SRZ) but not in the winter rainfall zone due to more complex environmental conditions. The third part deals with the Holocene hydrological and vegetation reconstruction in South Africa using a marine sediment core. The investigation reveals that towards the middle Holocene increasingly C4 plants abundance and wetter conditions occurred in the SRZ. During the last 4,000 years the SRZ experienced a gradual drying.